Latch



June 6, 1967 w. H. YAKE 3,323,822

LATCH Filed Dec. l, 1965 2 Sheets-Sheet 2 INVENTOR VV/LLKA/AM H. )fl/ 5,

United States Patent O 3,323,822 LATCH William H. Yake, Connersviile, Ind., assigner to Design and Manufacturing Corporation, Connersville, Ind., a corporation of Indiana Filed Dec. 1, 1965, Ser. No. 510,814 Ciaims. (Cl. 292-226) The invention relates to a latch mechanism, and more particularly to a latch mechanism comprising a hook-like strike and a lever actuated latch pin for engaging the strike.

For purposes of an exemplary showing, the latch mechanism of the present invention will be described in association with an under-counter dishwashing machine. This is not intended to constitute a limitation on the present invention, since the latch mechanism may find application in a number of uses wherein its general characteristics, hereinafter fully described, would be desirable.

In its exemplary application, the latch mechanism of the present invention is intended to serve as a closure means for that type of dishwasher wherein the vat or tub is located beneath a sink or counter top, and wherein the dishwasher has a front opening door. The bottom edge of the door is hinged to the dishwasher cabinet, and the door is swingable from a vertical closed position to a horizontal open position. The latch mechanism of the present invention provides a means whereby the door may be opened or closed, and latched securely in a closed position. When in its closed and latched position the mechanism may be provided with means for actuating a micro switch to initiate the dishwashing cycle. The dishwashing mechanism, however, cannot be started unless the door is fully closed and fully latched.

In its usual application to an under-the-counter dishwasher, the strike is axed to the dishwasher cabinet or tub, and the remainder of the latch mechanism including the lever and the strike engaging latch pin is located in and mounted on the door.

It is an object of the present invention to provide a latch mechanism characterized by simplicity `and compactness.

It is an object of the present invention to provide a latch mechanism having an over-center pivotal action, tending to hold the lever either in latch engaged position or in unlatched position. In the latter position, the micro switch actuating means firmly holds the micro switch in actuated condition.

It is an object of this invention to provide a latch mechanism which cannot be actuated to a closed position until the latch supporting door is moved to a predetermined space relationship with a tub mounted strike.

It is an object of the present invention to provide a latch mechanism wherein the latch pin engages the strike well before the door reaches its fully closed position, after which the mechanical advantage of the latch may be used to pull the door to its fully closed position.

It is an object ofthe invention to provide a latch mechanism having a minimum number of parts.

It is an object of the invention to provide such a latch mechanism which, although extremely compact, has a maximum distance between the latch pin and the pivot means for the latch actuating lever, whereby a maximum amount oi' mechanical advantage is secured.

These and other objects of the invention which will be described hereinafter or will be apparent to one skilled in the art upon reading this specification, are accomplished by that structure and arrangement of parts of which an exemplary embodiment will now be described. Reference is made to the accompanying drawings wherein:

FIG. 1 is a partial cross sectional view of the vat and 3,323,822 Patented June 6, 1967 ice door of an under-the-counter dishwasher, showing the application of the latch mechanism of the present invention.

FIG. 2 is a bottom view of the latch mechanism of the present invention in latch-open position.

FIG. 3 is a bottom view of the latch mechanism of the present invention in latch-closed position.

FIG. 4 is a perspective view of the latch housing.

FIG. 5 is a perspective view of the latch lever element.

FIG. 6 is a perspective view of the latch yoke element.

FIG. 7 is a perspective View of the strike.

In FIG. l the top flange of the dishwasher tub or vat is indicated at 1. The tub is provided with a gasket means indicated at 2. The top portion of the dishwasher door is shown at 3; and the door comprises an inner wall 3a and an outer wall 3b.

Referring to FIGS. 1 through 4, a latch housing, generally indicated at 4, comprises a portion 5, and another portion 6 which extends at a right angle to the portion 5. The base portion 5 may be provided with suitable slots such as are shown at 7 whereby it may be adjustably affixed to a mounting bracket 8 by suitable means such as bolts, screws or the like (not shown). The mounting bracket 8, in turn, is atixed to the inner Wall 3a of the door. The housing 4 has a lug 9, which may be an integral part of the base portion 5, and which lies in parallel spaced relationship to the housing portion 6. The base portion 5 of the housing 4 has an extension 10, angled with respect to the base portion and upon which a micro switch 10a (FIG. 2) may be mounted by suitable means. The micro switch 10a is adapted to make and break the conventional circuitry (not shown) controlling the cycles of operation of the dishwashing machine.

A lever element generally indicated at 11 and most clearly shown in FIG. 5, comprises a lever arm 12 which is an extension of one leg 13 of a U-shaped configuration having a base portion 14 and another leg 15. The legs 13 and 15 lie in parallel spaced relationship. The lever element 11 is pivotally aiixed to the housing 4 by means of a pivot pin 16 which extends through coaxial perforationsy in the housing lug 9, the legs 13 and 15 of the lever element and the housing portion 6.

The leg 13 of the lever element 11 is provided with a rounded projection 13a adapted to contact the plunger 10b of the switch 10a when the lever 12 is in its closed position as shown in FIG. 3. The leg 13 of the lever element is further provided with a laterally extending perforated lug 17 adapted to be engaged by one hooked end of the lever spring 18. The other hooked end of the lever spring is engaged in a notched lug 19 on the base portion 5 of the latch housing 4. The other leg 15 of the lever element 11 has an extension 20, the edge 20a of which serves as a latch trip abutment, while the edge 20h serves as a latch pin stop, all of which Will be more fully described hereinafter.

FIG. 6 shows in perspective a yoke element generally indicated at 21. The yoke 21 comprises a U-shaped element having a base portion 22, and legs 23 and 24. The yoke element 21 bears the latch pin 25, one end of which is aixed to the yoke leg 24, the other end of which extends through a perforation in the yoke leg 23.

As indicated in FIGS. 1 through 3, the yoke is pivotally aflixed to the lever element 11 between the legs 13 and 15 of the lever element. The legs of the lever element 11 are provided with coaxial perforations 26 and 27, and the legs of the yoke element 21 are provided with coaxial perforations one of which is shown at 28 in FIG. 6. A pivot pin 29 extends through the coaxial perforations in the legs of the lever element 11 and the coaxial perforations in the legs of the yoke element 21, so that the yoke element is pivoted to the lever element.

When the lever element 11 is in its unlatched position (see FIG. 2), the yoke element 21 is held within the legs 13 and 15 of `the -lever element in such a position that the end of the latch pin which extends beyond the yoke leg 23 rests on the edge 20h of the extension 20 of the lever element leg 15. This is enforced by means of a torsion spring 30, shown in FIG. 3. The convolutions of the torsion spring surround the yoke pivot pin 29. One end of the torsion spring is engaged by the latch pin 25 as at 31, while the other end of the torsion spring is engaged by the lever element pivot pin 16 as at 32.

As shown in FIG. 4, the latch housing 4 is provided with a trip generally indicated at 33. The trip 33 is pivoted as at 34 to an extension 6a of the housing portion 6. The trip is also provided with an inwardly extending trip pin 35. The trip pin 35, when the trip is in its normal position, rests on an edge 36 of the housing por- 'tion 6 (as indicated in FIG. 4). The trip and trip pin are held in this position by means of a spring 37, one end of which is engaged in a notch 38 in the extension 6a, and the other end of which is engaged in a perforation 39 in an outwardly extending lug 40 on the trip. The purpose and function of the trip and trip pin will be described more fully hereinafter.

FIG. '7 is a perspective view of the strike. The strike is generally indicated at 41 and is provided with a base 42. As shown in FIG. 1, the strike is afiixed by screws or the like (not shown) to the top flange of the dishwasher tub or vat 1. As also indicated in FIG. l, the strike is adapted to extend through a slot 43 or notch in Y the inner wall 3a of the dishwasher door, when the door Y is in its closed position.

The strike includes a hook 44, a latch pin guide surface 45, a trip cam 46 and ya 4trip bearing edge 46a. The function and purpose of these elements will be described more fully below.

Briefly, the operation of the lever mechanism of the present invention is as follows:

FIG. 2 illustrates the latch mechanism in its open position. It will be noted that the latch pin 25 rests on the edge 20b of the lever element leg 15 and on the depressed edge portion 46 of the lever housing portion 6. In the absence of the strike, the lever 12 cannot be traversed to a position where the projection 13a engages the plunger 10b of the Imicroswitch 10a because such traversing movernent will be stopped by the abutment of the edge 20a of the extension 2t) on the lever element against the pin of the trip 33.

A comparison of FIG. 2 with FIG. 3 (which shows the latch in closed position) and with FIG. 1 (which shows the latch in an open position) will indicate that as the door 3 is brought to a nearly closed position, the strike 41 will enter through the slot 43 in the inner wall 3a of the door. The trip cam surface 46 on the strike will first engage the lug of the tripr33 causing the trip and its pin 35 to pivot to the position shown in FIG. 3, against vthe action of the spring 37.Y With the trip 33 and the trip pin 35 in this position, and maintained in this position by bearing against the edge 46a of the strike, the lever 1,2 forming a part of the lever element 11 is free to pivot about the pin 16, in the direction of arrow A in FIG. 3. As the lever element assembly is pivoted, it carries with it the yoke element 21 and the latch pin 25 until the latch pin 25 engages the latch pin guide surface 45 of the strike. The latch pin 25 continues to ride on the strike surface until it engages the inside surface of the strike hook 44. This causes the yoke to begin to pivot against the action of the torsion spring 30 about the pivot pin 29. As the lever 12 continues its traversing movement in the direction of the arrow A, the yoke continues to pivot with respect to the lever element 11 until the fully closed position is attained by the latch mechanism, and the yoke pivot pin 29 is carried beyond an imaginary line drawn between the lever pivot pin 16 and the latch pin 25. This will be apparent from FIG. 3. The toggle action and over-center movement causes the door 3 to be pulled forcibly to its closed position. It will be noted from FIG. 3 that the lever spring 18 has its ends so located that it pulls in an over-center fashion to either hold the lever element in an open position or to help hold it in a closed position. In its fully closed position, as illustrated in FIG. 3, the projection 13a depresses the switch plunger 10b to initiate the dishwashingY cycle by means of circuitry well known in the art.

While the latch mechanism herein described is extremely compact, it will 'be noted by one skilled in the art that there is a maximum distance obtained between the latch pin 25 and the lever element pivot pin 16, whereby a maximum amount of mechanical'advantage is secured from the latch mechanism. The latch pin is caused to engage the strike while the door is not yet fully closed, so that use may be made of the mechanical advantage of the latch mechanism to pull the door to its fully closed position with a minimum amount of effort by the user. It will further be noted that the relative positions of the latch pin 25, the trip abutment surface 20a, the yoke pivot pin 29 and the hook 44v of the strike are such that the lever cannot be moved to a lclosed position until the latch pin is behind the hook 44 of the strike, so that as the strike engages the trip and frees the lever to move to its fully closed position, the latch pin will be caught by the hook 33 of the strike 41.

When the lever 12 is moved in a direction opposite to that indicated by the arrow A, the latch pin 25 will disengage the hook 44 of the strike, the strike will disengage the trip 33, and the elements will be free to return to the position shown in FIG. 2.

The operating lever arm 12 Vextends through a slot 47 in the front wall 3b of the door, and is provided with a convenient handle 48. Needless to say, the door may have a decorative escutcheon'suitably marked for open and closed positions of the latch lever.

Modifications lmay be made in the invention without departing from the spirit of it.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a latch mechanism, a base having angularly dis- Y posed interspaced legs for the acceptance of a pivot pin, a lever element pivoted to said legs and capable of assuming two positions, a yoke element pivoted to said lever element, a latch pin mounted in said yoke at a position remote from the pivot point of said yoke, said latch pin being prolonged beyond said yoke so as to engage one of the legs of said base to detenmine one of the positions of said lever and so as to be engageable with a strike, a trip element pivoted on one of the legs of said base, a configuration on said lever element for engaging said trip element to block said lever element from assuming the other of said positions and a strikev having a portion configured to move said trip element to nonblocking position, and a hook portion for engagement with said latch pin.

2. The structure claimed in claim 1 including a tension spring connecting said lever element to said base, said spring having an over-center relationship with said lever element so as to tend to retain in it either of the said positions.

3. The structure claimed in claim 2 including a spring acting between said lever element and said yoke element and biasing said yoke element toward said strike.

4. The structure claimed in claim 2 wherein said lever element has at its pivoted end a U-shaped configuration with spaced leg portions, the said yoke element being located between said leg portions and pivoted thereto.

5. The structure claimed in claim 4 wherein said lever element'comprises .a lever which is an extension of one of said last mentioned legs, the said configuration for engaging said trip element being located on the other of said last mentioned legs.

6. The structure claimed in claim 5 wherein said base has an extension, an electric switch having an operating portion mounted on said extension, the said operating portion being in alignment with a portion of said lever element so as to be actuable thereby when said lever element is moved fully to said other of said positions.

7. The structure claimed in claim 6 in which the said conguration coacting with said trip element is located on the leg of said lever element remote from said lever.

MARVIN A. CHAMPION, Primary Examiner.

1/1934 Brainerd. 12/ 1937 Komenak. 10/ 1961 Jellies. 12/1961 Van Noord RICHARD E. MOORE, Examiner. 

1. IN A LATCH MECHANISM, A BASE HAVING ANGULARLY DISPOSED INTERSPACED LEGS FOR THE ACCEPTANCE OF A PIVOT PIN, A LEVER ELEMENT PIVOTED TO SAID LEGS AND CAPABLE OF ASSUMING TWO POSITIONS, A YOKE ELEMENT PIVOTED TO SAID LEVER ELEMENT, A LATCH PIN MOUNTED IN SAID YOKE AT A POSITION REMOTE FROM THE PIVOT POINT OF SAID YOKE, SAID LATCH PIN BEING PROLONGED BEYOND SAID YOKE SO AS TO ENGAGE ONE OF THE LEGS OF SAID BASE TO DETERMINE ONE OF THE POSITIONS OF SAID LEVER AND SO AS TO BE ENGAGEABLE WITH A STRIKE, A TRIP ELEMENT PIVOTED ON ONE OF THE LEGS OF SAID BASE, A CONFIGURATION ON SAID LEVER ELEMENT FOR ENGAGING SAID TRIP ELEMENT TO BLOCK SAID LEVER ELEMENT FROM ASSUMING THE OTHER OF SAID POSITIONS AND A STRIKE HAVING A PORTION CONFIGURED TO MOVE SAID TRIP ELEMENT TO NONBLOCKING POSITION, AND A HOOK PORTION FOR ENGAGEMENT WITH SAID LATCH PIN. 